In addition to the firefighters, 12 fire engines were called out to the Brucefield Industrial Park, in response to an alarm at the packaging printer just before midday yesterday.

One employee was taken to St Johns hospital in Livingston where they are being treated for suspected burns to their arm.

A spokeswoman for Lothian and Borders Fire and Rescue Service told PrintWeek this morning that three firefighters were sent to a nearby hospital overnight due to over-exposure to the fire.

She added: "Firefighters had to withdraw from fighting inside the building because there were concerns over the building collapsing and highly volatile chemicals. We were there overnight and are still on site cooling, we would expect to be there for several hours at least."

According to the company, there is "significant" damage to the main facility, as well as the company's secondary buildings.

A statement from Amcor said: "The well-being and safety of all co-workers at the site is Amcor’s top priority. Its culture of customer and market focus and dedication to seamless operations means an action plan to meet customers’ needs through alternative sourcing is already fully active.

"Amcor thanks all involved, particularly the local emergency services, for their quick response."

Local residents were advised to stay indoors and keep doors and windows closed because of fears over possible toxic fumes from the chemicals. Other businesses on the Brucefield Industrial estate have been also been evacuated.

The fire service spokeswoman added: "Our main priority was cooling the cylinders and we are using three height appliances as water towers to facilitate this.

"We are working with other agencies, including the Police on the implications for nearby residents and also SEPA to address environmental issues. Plumes of thick, black smoke can be seen for miles around."